OCTAXDRIA TKIGYN1A 247 



Order 3. Trigyiiia. 



201. POLYGONUM. L. Jfutt. Gen. 370. 

 [Greek, Polys, many, and Gonu, a knee, or joint; the stem being much jointed] 



Perianth mostly 5-parted, colored or corolla-like, persistent. Stamens 

 5 to 9, mostly 8. Ovary superior ; stifles 2 or 3. Seed or Nut solitary, 

 compressed, or triquetrous, mostly covered by the persistent perianth. 



Herbaceous : stem jointed ; leaves alternate, adhering at base to sheathing sti- 

 pules ; flowers in axillary and terminal clusters and spikes, or paniculate racemes. 

 Nat. Ord. 15G. Lindl. Polygoke.e. 



| Flowers axillary. 



1. P. aviculare, L. Stem mostly procumbent; leaves elliptic-lance- 

 olate, acute, narrow, sessile ; flowers subsessile. Beck, Hot. p. 300. 

 P. aviculare, var. angustifolium. Mx.Am. I. p. 237. Pursh, Am* 1. 

 p. 269. Mitt. Gen. 1. p. 254. Bart. Phil. I. p. 186. 



Bird Polygonum, Vulgd — Knot-grass. 



Gallice — Trainasse. Germanicc — Der Wegetritt, His p. — Centinodia. 



Root annual, subligneous, fibrous. Stem G to 12 or 15 inches long, slender, more 

 or less procumbent, much branched, striate, smooth. Leaves half an inch to an 

 inch long, and 1 eighth lo 1 third of an inch wide, varying from linear-lance- 

 olate and acute to elliptic and oblanceolate, attenuate at base, sessile, smooth, 

 urabrous on the margin. Stipules scarious, white, remotely nerved, parted into 

 lanceolate acuminate segments at .summit. Flowers small, in axillary clusters of 

 2 to 3, subsessile. Perianth L r reen, the segments edged with while, and often tinged 

 with purple. Stamens often 5 (8, Authors). Stigmas 3, subsessile, diverging. 

 Seed ovoid-triquetrous, acuminate, punctate-striatc, dark brown. 



J fab. About houses, gardens, foot-ways, &c. common. Fl. June, Oct. Fr. Aug. Nov. 



Obs. This has every appearance of being an introduced plant, in all its local- 

 ities here. 



2. P. erectum, In Stem mostly erect ; leaves broad-oval, or elliptic- 

 oblong, rather obtuse, subpetiolatc ; flowers pedicellate, pentandrous. 

 Beck, BoU p. 300. 



P. aviculare, var. latifolium. Mx. Am. 1. p. 237. Pursh, Am. I. p. 

 269. JSTutt. Gen. I. p. 254. Bart. I J hiL 1. p. 186. Torr. Fl. I. p. 400. 



Erect Polygonum. 



Plant often yellowish green. Root annual? subligneous, fibrous. Stern 1 to 2 

 and 3 feet high, mostly erect, sometimes decumbent, branched, striate, smooth; 

 lower branches spreading, assurgent. Leaves half an inch to 2 inches long, and 1 

 fourth to 3 fourths of an inch wide, obtuse, or sometimes rather acute, smooth, mi- 

 nutely scabrous on the margin, — the stem leaves considerably larger than those on 

 the branches, and distinctly petiolatc. Stipules scarious, brownish, remotely 

 nerved, lacerate at summit. Flowers in axillary clusters of 2 or 3, distinctly pedi- 

 cellate. Perianth yellowish green. Styles 3, very short* Seed triquetrous, some- 

 what striate-punctatc, brown. 



flab. About houses, yards, and r^arlens : frequent. Fl. Aug.-Octo. Fr. Sept.-Nov. 



Obs. This is readily distinguished, by its size and habit, from th€ preceding ; 

 but it must be confessed, when we come to the botanical details, that they are near- 

 ly allied. 



